Raddish

Radish : Raphanus sativas L.

Introduction

Radish (Raphanus sativus L), which originated from Europe or Asia, is presently cultivated all over the world. In Sri Lanka, Radish is one of the vegetables that can be grown in all agro ecological regions throughout the year if adequate moisture is available. Two varieties, Japan ball Rabu and Beeralu Rabu are recommended for upcountry and low country respectively. Long and red/spring radishes that are mainly used for salad and decorative purposes have high demand for hotel industry. In addition, radish is used for pickling and other processing industries. Radish is widely cultivated in the districts of Nuwaraeliya, Badulla, Kalutura and Galle. Among other districts where it could be successfully grown are Kandy, Matale, Gampaha and Ratnapura.


Nutritive value
Radish is used as vegetable or salad in Sri Lanka. The major component in the edible portion of radish (per 100g) is water that amounts 94.5%. Further, it contains protein, fat, carbohydrate, fiber and ash, which account 1.0, 0.1, 306, 0.7 and 0.8 grams respectively. The vitamins and minerals (100g) that consists in radish are follows

Vitamin A (IU)

10

Thiamin (mg)

0.03

Riboflavin (mg)

0.03

Niacin (mg)

0.3

Ascorbic acid (mg)

26

Calcium (mg)

30

Phosphorus (mg)

31

Iron (mg)

1.0

Sodium (mg)

18

Potassium (mg)

322


Source: Department of Food and Nutrition, American Medical Association, Futura Publishing Co.1974.

Recommended varieties
Varietal characters of recommended varieties

1. Japan ball
Roots - Round, white skin
Leaves - lobed to mid-rib pubescent
Harvest time - 45-55 days
2. Beeralu rabu
Roots - Spindle shape, white skin
Leaves - neither lobed nor pubescent
Harvesting time - 45 -50 days
3. Table radish
Roots - Marble size, red can be eaten raw
Harvesting time - 35-40 days

Field establishment

Climate
Radish can be grown in all agro ecological regions

Soils
Well drained soils with a pH range of 6.0 - 7.5 is more suitable

Land preparation
Soils should be ploughed to a depth of 30-40 cm to provide fine tilth

Seed rate
5 kg/ha

Seed production
Unlike other exotic vegetables, seeds of radish could be produced under local climatic conditions

Procedure
1. Isolation
A radish crop should be isolated from other radish crops by the following
distances.
Basic seed crops- 1600 m; Standard seed crops- 1000m. If any species
of wild radish or mustard are found within the isolation distances during
flowering, the seed crop will be rejected.
2. Time of planting - Mid November
3. Spacing - 1' - 1 ' X 1' - 1 '

Basic seed production - Harvest the tubers 4-6 weeks after planting and transport the uniform tubers of the harvest for seed production.


Standard seed production
i. Non uniform plants should be roughed out before flowering stage to maintain the purity of the variety.
ii. At flowering stage, rough out the non uniform plants according to the colour of flowers
Standard colour of the petals
Beeralu - Purple and white
Japan ball - Mostly white. Sometimes white and purple

Seed Requirement

The popular varieties Japan Ball Rabu and Beeralu Rabu are widely cultivated by the farmers in the Up country and Low country respectively. The private sector, farmer organization and the farmers are the major source of seed supply. Department of Agriculture is supplying the total demand of Basic seed of Beeralu Rabu while seeds of Ball Rabu is imported by various private companies. Seeds of all the other varieties (Long and Red radish) available in the market are also supplied by the private sector.


Seed Requirement & Source of supply of Radish - Beeralu & Ball during 1998-2002.

Requirement source

1998

1999

2000

2001

2002
Of supply

Required Quantity (mt)

11.3

11.9

12.7

13.31

14.0

Supplied by DOA

0.4

3.5

3.0

3.0

1.5

Private sector

1.0

3.5

5.0

6.8

9.0

Farmer organization Farmers

1.8

1.4

1.7

1.5

1.5

Imports by thePrivate sector

4.5

3.5

3.0

2.0

2.0

% Formal supply

84

88

86

88

89

Source: DOA task force report, 1998.

Time of planting
In upcountry, only during March to May and August to October to avoid flowering

Planting and spacing
i. Dibble in rows on raised beds
ii. Spacing - 25-30 cm between rows; 10cm between plants
iii. Spacing for table radish - 20 cm X 5 cm
iv. Plant 2 seeds per hill and thin out one at germination

Crop management

Fertilizer use
Basal (At planting)
i. Urea -90kg/ha
ii. Tri super phosphate - 110 kg/ha
iii. Muriate of potash - 65 kg/ha

Top dressing (3 weeks after planting)
i. Urea - 90 kg/ha
ii. Muriate of potash - 65 kg/ha

Irrigation
Irrigate daily for the first 4-5 days; then every 3-4 days depending on rainfall

Weed control
One hand weeding 4 weeks after planting for the up country and 2 weeks after planting for the low country

Major pest and disease control
Disease
Club root
Symptom
Swelling/ malformation on the main root and laterals
Stunted growth

Control

  • Raise soil pH with heavy dressing of lime
  • Avoid continuous cropping of crucifers
  • Keep the field free of wild mustard


Pests
Leaf eating caterpillars
Control: Apply chlorofluazuran, Quinalphos, Profenophos, Etofenprox or neem seed water extract

Vegetable leaf miner - Liriomyza huidobrensis
(Diptera: Agromyzidae)

Damage

On foliage, larvae make on lower leaf surfaces and usually are associated with the midrib and lateral veins. A mine usually begins on the upper leaf surface and moves to the lower surface after a few millimeters of feeding by the larva. Adults punching leaves for both feeding and oviposition. Punctures and mines may be numerous enough to greatly reduce photosynthesis and may kill young plants. These mines and punctures further reduced the value of ornamental plants.


Regulatory Action

Inspection of the fields before and after cultivation of the crop is needed for the proper management of the Liriomyza huidobrensis. Knowledge on cropping pattern and distribution pattern of the leaf miner in the region is important to achieve successful management of this pest.


Inspection of crop

  1. Yellow traps - Yellow colour boards with sticky substances can be placed in the field. If adult flies present, they trap into these boards. This will enable to farmer to get an idea on population of the flies.
  2. Inspection of the punch markers on the foliage.


Chemical control

  1. Neem seed kernel water Extract
    This can be applied at the rate of 2 g / l in 3 - 4 day intervals. This method need to practice from at the beginning of the seedling emergence.
  2. Neemazal - F: 1 - 2 ml per one liter of water, apply on seven days interval
  3. Two kinds of translaminar insecticides cyromazin and abamactine are recommended for the control of leaf miner larvae on foliage.


Biological control

Diglypus isaea, a hymenopteran parasitoid was introduced in 1998. At present this it is well established in the region. Later, two local hymenopteran parasitoids, Hemiptarsenoideus semiabiclavus and Opius spp. were identified. However introduced parasitoid is showing more than 80% of the parasitism compared to two other parasitoids in the region.


Cutworms - Agrotis spp. and other Noctuidae species
They are the larvae of several noctuid moths species that cut through the stems of young plants. Robust and grayish larvae as long as 5 cm remain buried at the base of the plant during the day. Roots closer to the ground surface may suffer occasional damage. Some species will preferably feed on the leave.

Control

Spotted or localized field infestations are typical, calling for focused insecticides treatments and it should be applied at the base of plants at dusk


Harvesting & post-harvest technology

Yield
Japanese ball - 40-50 t/ha
Beeralu - 20-30 t/ha

Harvest
Harvesting should be done at proper time. Delay in harvesting reduces the quality of radish by accumulating high amount of fibrous

Post-harvest practices

  • Grade roots and handle them carefully to avoid mechanical damage
  • Pack roots in well ventilated containers if transport long distances
  • Economics & marketing


Extents and Production


Extent and production of Radish cultivation during 1991- 2002

Year

Extent (ha)

Total Production
(Mt)

Productivity
(Mt/ha)

1991

2228

18974

8.5

1992

2098

18912

9.0

1993

2146

20252

9.4

1994

2101

19901

9.5

1995

2091

18550

8.9

1996

2241

19830

8.8

1997

2307

21516

9.3

1998

2559

22139

8.7

1999

2715

25891

9.5

2000

2742

26039

9.5

2001

2727

25327

9.3

2002

2468

22426

9.1

Source: Department of Census & Statistics

District wise extent and production

The District wise estimated extents and production for 2000/2001 Maha, 2001 Yala and 2001/2002 Maha are given in Table. The districts of Nuwara Eliya, Badulla, Matara, Moneragala, Ratnapura, Kandy, Kurunegala, Kalutara, Galle and Hambantota will be the major contributors to the total production in the future.

District wise Extent and Production during 2000/2001 Maha, 2001 Yala and 2001/2002 Maha.

District

2000/2001 Maha

2001 Yala

2001/2002 Maha

Area

Production

Area

Production

Area

Production

Colombo

8

124

8

120

8

131

Gampaha

5

80

5

75

5

86

Kalutara

34

512

32

500

36

557

Galle

30

452

27

420

31

480

Matara

141

2107

131

1975

148

2260

Hambantota

26

393

24

370

28

435

Badulla

243

3627

226

3400

255

3886

Moneragala

73

1094

67

1015

76

1165

Ratnapura

70

1048

66

1000

74

1135

Kegalle

15

228

14

220

15

238

Kurunegala

84

1257

78

1180

88

1147

Puttalam

21

318

20

310

22

344

Kandy

64

959

60

920

67

1028

Matale

28

422

26

400

29

450

Nuwara Eliya

409

6099

381

5725

428

6516

Anuradhapura

21

318

20

310

22

344

Polonnaruwa

3

50

3

45

3

55

Jaffna

-

-

-

-

-

-

Kilinochchi

-

-

-

-

-

-

Mannar

-

-

-

-

-

-

Vavuniya

4

65

2

40

4

70

Mulativu

-

-

-

-

-

-

Trincomalee

-

-

-

-

-

-

Batticaloa

-

-

-

-

-

-

Ampara

4

65

3

55

4

70

Udawalawe

23

348

21

325

24

375

System H

10

154

9

145

10

160

System B

7

109

6

100

7

115

System C

15

228

14

220

15

238

System G

-

-

-

-

-

-

System L

7

109

6

100

7

115

Total

1345

20166

1249

18980

1408

21402

Source: Based on DOA task force report, 1998

Export value
Only small quantities of radish are exported mainly to Middle East countries
(Source: Customs department, 1997).

Production cost

Labour (73%) is the highest cost component in radish cultivation, follows with seed (18%), pesticide (6%) and fertilizer (3%) (Source: Department of Census and Statistics, 1996). The unit cost of production for the period of 1998-2001 is given in Table. The estimated production cost indicates that increasing the productivity of the crop by adopting appropriate technologies could reduce the unit cost of production.


Estimated cost of production (COP) for Radish during 1998-2001.
(Assumed cost of production of 30,700 Rs/ha & Average produces price of 4.12 Rs/kg)

Year

Average yield (kg)

Unit COP

Net Return
(Rs/kg)

1998

14,000

2.19

26980

1999

15,000

2.04

31100

2000

15,000

2.04

31100

2001

15,200

2.01

31924


Cost of Production

Labour (73%) is the highest cost component in radish cultivation, follows with seed (18%), pesticide (6%) and fertilizer (3%) (Source: Department of Census and Statistics, 1996).

Adoption of following strategies could reduce the production cost

  • Efficient labour management
  • Usage of high quality seed material
  • Adoption of IPM package
  • Usage of straight fertilizer


Quality improvement for Export

Uniform shape, length (> 15 cm) and width (6-8 cm) with white skin color are the requirements for export market. In addition, the skin should be free of blemishes, physical injuries and pest and disease damages. Usage of proper varieties, adoption of appropriate management practices and pre and post harvest handling improve the quality of produce for export market.


Progress indicators

Increase in productivity, total production, per capita consumption, extent under cultivation and demand and volume for export are the progress indicators for the expansion of radish cultivation.